Green Design Features

Reference Packet

NOTE: This is by no means an exhaustive list of

possible Green Design Features, but is meant to give

you some ideas for your home design. If you have

other ideas to make your home environmentally

friendly, by all means use them.

Green Design Feature: Generating Renewable Energy from Solar Panels

Description:

Solar cells, also called photovoltaic (PV) cells by scientists, convert

sunlight directly into electricity. PV gets its name from the process

of converting light (photons) to electricity (voltage), which is called

the PV effect. The PV effect was discovered in 1954, when scientists

at Bell Telephone discovered that silicon (an element found in sand)

created an electric charge when exposed to sunlight. Soon solar

cells were being used to power space satellites and smaller items

like calculators and watches. Today, thousands of people power

their homes and businesses with individual solar PV systems. Utility companies are also using PV technology

for large power stations.

Solar panels used to power homes and businesses are typically made from solar cells combined into modules

that hold about 40 cells. A typical home will use about 10 to 20 solar panels to power the home. The panels

are mounted at a fixed angle facing south, or they can be mounted on a tracking device that follows the sun,

allowing them to capture the most sunlight. Many solar panels combined together to create one system is

called a solar array. For large electric utility or industrial applications, hundreds of solar arrays are

interconnected to form a large utility-scale PV system.

The main benefits of solar energy are:

Solar energy systems do not produce air pollutants or carbon-dioxide

When located on buildings, they have minimal impact on the environment

Limitations of solar energy are:

The amount of sunlight that arrives at the Earth's surface is not constant. It varies depending on

location, time of day, time of year, and weather conditions.

Because the sun doesn't deliver that much energy to any one place at any one time, a large surface

area is required to collect the energy at a useful rate.

Solar panels can be quite expensive to purchase initially.

Sources: http://www.nrel.gov/learning/re_photovoltaics.html

http://www.eia.gov/kids/energy.cfm?page=solar_home-basics#top-container

Conditions for this Green Design Feature to be practical: Lots of sun!

The Zion National Park Visitor Center

incorporates passive solar design

features, including clerestory windows

for daylighting and Trombe walls that

absorb heat during the day and give off

heat at night.

Green Design Feature: Heating and Lighting Your House with Passive Solar Energy

Description:

The south side of a building always receives the most sunlight. Therefore, buildings designed for passive solar

heating usually have large, south-facing windows. Materials that absorb and store the sun's heat can be built

into the sunlit floors and walls. The floors and walls will then heat up during the day and slowly release heat

at night, when the heat is needed most. This passive solar design

feature is called direct gain.

Other passive solar heating design features include sunspaces and

trombe walls. A sunspace (which is much like a greenhouse) is built

on the south side of a building. As sunlight passes through glass or

other glazing, it warms the sunspace. Proper ventilation allows the

heat to circulate into the building. On the other hand, a trombe

wall is a very thick, south-facing wall, which is painted black and

made of a material that absorbs a lot of heat. A pane of glass or

plastic glazing, installed a few inches in front of the wall, helps hold

in the heat. The wall heats up slowly during the day. Then as it

cools gradually during the night, it gives off its heat inside the

building.

Many of the passive solar heating design features also provide daylighting. Daylighting is simply the use of

natural sunlight to brighten up a building's interior. To lighten up north-facing rooms and upper levels,

aclerestory—a row of windows near the peak of the roof—is often used along with an open floor plan inside

that allows the light to bounce throughout the building.

Of course, too much solar heating and daylighting can be a problem during the hot summer months.

Fortunately, there are many design features that help keep passive solar buildings cool in the summer. For

instance, overhangs can be designed to shade windows when the sun is high in the summer. Sunspaces can

be closed off from the rest of the building. And a building can be designed to use fresh-air ventilation in the

summer.

Source: http://www.nrel.gov/learning/re_passive_solar.html

Conditions for this Green Design Feature be practical: Heating will work in most locations, but may

not be as desirable in a tropical location, since you are trying to keep your home cool. Natural light is useful

anywhere, although will have limited use in locations far to the north or south, with seasons that have very

little daylight.

Green Design Feature: Heating your Water with Solar Energy

Description:

The shallow water of a lake is usually warmer than the deep water. That's because the sunlight can heat the lake

bottom in the shallow areas, which in turn, heats the water. It's nature's way of solar water heating. The sun can be

used in basically the same way to heat water used in buildings and swimming pools.

Most solar water heating systems for buildings have two main parts: a solar collector and a storage tank. The most common collector is called a flat-plate collector. Mounted on the roof, it consists of a thin, flat, rectangular box with a transparent cover that faces the sun. Small tubes run through the box and carry the fluid — either water or other fluid, such as an antifreeze solution — to be heated. The tubes are attached to an absorber plate, which is painted black to absorb the heat. As heat builds up in the collector, it heats the fluid passing through the tubes.

The storage tank then holds the hot liquid. It can be just a modified water heater, but it is usually larger and very well-insulated. Systems that use fluids other than water usually heat the water by passing it through a coil of tubing in the tank, which is full of hot fluid.

Solar water heating systems can be either active or passive, but the most common are active systems. Active systems rely on pumps to move the liquid between the collector and the storage tank, while passive systems rely on gravity and the tendency for water to naturally circulate as it is heated.

Swimming pool systems are simpler. The pool's filter pump is used to pump the water through a solar collector, which is usually made of black plastic or rubber. And of course, the pool stores the hot water.

Source: http://www.nrel.gov/learning/re_solar_hot_water.html

Conditions for this Green Design Feature to be Practical: Similar to solar panels generating electricity,

you need to have enough sunlight to heat the water.

Green Design Feature: Generating Renewable Energy from Wind Turbines

Description:

We have been harnessing the wind's energy for hundreds of years. From old Holland to farms in the United States, windmills have been used for pumping water or grinding grain. Today, the windmill's modern equivalent—a wind turbine—can use the wind's energy to generate electricity.

Wind turbines, like windmills, are mounted on a tower to capture the most energy. At 100 feet (30 meters) or more aboveground, they can take advantage of the faster and less turbulent wind. Turbines catch the wind's energy with their propeller-like blades. Usually, two or three blades are mounted on a shaft to form a rotor.

Wind turbines can be used as stand-alone applications, or they can be connected to a utility power grid or even combined with a photovoltaic (solar cell) system. For utility-scale (megawatt-sized) sources of wind energy, a large number of wind turbines are usually built close together to form a wind plant, also referred to as awind farm. Several electricity providers today use wind plants to supply power to their customers.

Stand-alone wind turbines are typically used for water pumping or communications. However, homeowners, farmers, and ranchers in windy areas can also use wind turbines as a way to cut their electric bills.

Source: http://www.nrel.gov/learning/re_wind.html

Conditions for this Green Design Feature to be Practical: You need 7 mph (6 knots, 11 km/h) to get

a wind turbine started and average at least 10-12 mph (8-10 knots, 16-19 kph)for 6 hours a day to generate electricity.

Green Design Feature: Geothermal Energy

Description:

Many technologies have been developed to take advantage of geothermal energy—the heat from the earth. This heat can be drawn from several sources: hot water or steam reservoirs deep in the earth that are accessed by drilling; geothermal reservoirs located near the earth's surface, mostly located in the western U.S., Alaska, and Hawaii; and the shallow ground near the Earth's surface that maintains a relatively constant temperature of 50°-60°F.

Direct Use: In modern direct-use systems, a well is drilled into a geo thermal reservoir to provide a steady stream of hot water. The water is brought up through the well, and a mechanical system—piping, a heat exchanger, and controls—delivers the heat directly for its intended use. A disposal system then either injects the cooled water underground or disposes of it on the surface.

Geothermal hot water can be used for many applications that require heat. Its current uses include heating buildings (either individually or whole towns), raising plants in greenhouses, drying crops, heating water at fish farms, and several industrial processes, such as pasteurizing milk.

Geothermal heat pumps take advantage of the nearly constant temperature of the Earth to heat and cool buildings. The shallow ground, or the upper 10 feet of the Earth, maintains a temperature between 50° and 60°F (10°–16°C). This temperature is warmer than the air above it in the winter and cooler in the summer.

Heat Pumps: Geothermal heat pump systems consist of three parts: the ground heat exchanger, the heat pump unit, and the air delivery system (ductwork). The heat exchanger is a system of pipes called a loop, which is buried in the shallow ground near the building. A fluid (usually water or a mixture of water and antifreeze) circulates through the pipes to absorb or relinquish heat within the ground.

Heat pumps work much like refrigerators, which make a cool place (the inside of the refrigerator) cooler by transferring heat to a relatively warm place (the surrounding room), making it warmer. In the winter, the heat pump removes heat from the heat exchanger and pumps it into the indoor air delivery system, moving heat from the ground to the building's interior. In the summer, the process is reversed, and the heat pump moves heat from the indoor air into the heat exchanger, effectively moving the heat from indoors to the ground. The heat removed from the indoor air during the summer can also be used to heat water, providing a free source of hot water.

Geothermal heat pumps use much less energy than conventional heating systems, since they draw heat from the ground. They are also more efficient when cooling your home. Not only does this save energy and money, it reduces air pollution.

All areas of the United States [Ms. Weaver’s comment: and worldwide, presumably] have nearly constant shallow-ground temperatures, which are suitable for geothermal heat pumps.

Source: http://www.nrel.gov/learning/re_geo_heat_pumps.html

Conditions for this Green Design Feature to be Practical: Direct use requires an active geothermal area, but heat pumps can work pretty much anywhere.

Micro Hydropower

A micro hydropower plant has a capacity of up to

100 kilowatts. A small or micro-hydroelectric power

system can produce enough electricity for a home,

farm, ranch, or village.

Green Design Feature: Generating Renewable Energy from Hydropower

Description:

Hydropower is using water to power machinery

or make electricity. Water constantly moves

through a vast global cycle, evaporating from

lakes and oceans, forming clouds, precipitating

as rain or snow, then flowing back down to the

ocean. The energy of this water cycle, which is

driven by the sun, can be tapped to produce

electricity or for mechanical tasks like grinding

grain. Hydropower uses a fuel—water—that is

not reduced or used up in the process. Because

the water cycle is an endless, constantly

recharging system, hydropower is considered a

renewable energy.

When flowing water is captured and turned into electricity, it

is called hydroelectric power or hydropower. There are

several types of hydroelectric facilities; they are all powered

by the kinetic energy of flowing water as it moves

downstream. Turbines and generators convert the energy

into electricity, which is then fed into the electrical grid to be

used in homes, businesses, and by industry. Hydropower

plants range in size from small systems for a home or village

to large projects producing electricity for utilities.

Source: http://www1.eere.energy.gov/water/hydropower_resources.html

Conditions for this Green Design Feature to be Practical: Obviously, to use water as a source of

power, you need to be near water, and water that is flowing fast enough to spin a turbine and generate power, which probably means a stream or river.

Green Design Feature: Re-Using Water

Description:

Conserving water is a great place to start. Running your dishwasher and washing machine only for full loads, for example, can cut a household's water consumption by an average of 1,000 gallons a month. For some, though, simple water conservation doesn't go far enough. One thing they may consider is recycling their home's gray water.

Gray water is all of the wastewater that drains out of your washing machine, sinks and bathtub or shower. It can be easily treated and recycled in your home. In developing countries, the concept of reusing water is old and established, but in other nations where people consider water plentiful, it's used once and thrown away.

Using gray water is certainly a good idea, but it also has its drawbacks. While gray water is a lot less harmful to people than the wastewater that leaves your toilet -- called black water -- it's still technically sewage. The amounts of these wastes are small enough to prevent gray water from going through the treatment process that black water does, but you still shouldn't drink it. Your plants, however, will love your bath water.

As a matter of fact, irrigation for lawns and gardens is the only advisable application for using gray water. The United States Environmental Protection Agency says that, in 2007, water used for irrigation constituted 15 percent of total water consumption in the United States [source: EPA]. And this was first-run water -- the same stuff you drink.

Your plants don't necessarily need fresh water, and what's more, some additives in gray water can actually help them grow. Cleaning agents found in laundry detergent -- stuff like phosphorus and nitrogen -- are actually used in many plant fertilizers sold on the market. Some plants, however, like gray water more than others. Since gray water is alkaline-rich, it's not suitable for use in watering acid-loving plants like azaleas and rhododendrons.

If you look around your house, you'll find a number of different places where you can find and reuse water. A free-standing outdoor air-conditioning unit produces 10 to 15 gallons of condensation on a hot day, and all of this is wasted [source:Free Patents Online]. There are some condensate collection kits available in stores that can collect your A/C unit's condensation and send it to an irrigation system.

You can also collect water from a window-mounted air conditioning unit. Simply place a bucket underneath the system to catch the condensation that drips from it. You can add a drip irrigation system to the bucket for low-maintenance plant watering. What's great about using A/C units as a source for reusable water is that they produce the most condensation during the hottest months, when watering bans are most prevalent.

Bath water is considered the best source for gray water, but collecting it using a bucket can be tedious and backbreaking. One British company figured out a way to collect bath water easily with the Ban Beater. This system uses a hose and suction to siphon the water into a cistern, which can b e toted outside and used for localized watering.

Perhaps the easiest place to collect gray water, though, is from your clothes washer. Most models have a drain pipe exiting the back of the washer. Water can be easily removed from the drain to the sewer and placed into collection buckets. Just be sure, when collecting gray water with this method, that you have enough buckets and quick reflexes to catch all of the water exiting your washer during the drain cycle.

Source: http://tlc.howstuffworks.com/home/gray-water.htm

Conditions for this Green Design Feature to be Practical: Reusing your water can work anywhere, but

is especially important in dry areas with a water shortage or drought.

Green Design Feature: Green Roofs

Description:

Cities worldwide are promoting environmentally “green” roofs to mitigate several urban problems. Ground

cover, shrubs and other flora planted across a building’s roof can reduce storm water runoff, easing the

burden on local sewers and water treatment systems. And the vegetation can keep the roof cooler in

summer, lowering interior air-conditioning costs and therefore peak demand on area power plants.

Green roofs provide a number of other advantages. The most obvious of these is their positive impact on the environment. When we build houses, some of the land and vegetation is displaced, destroyed or removed all together. Obviously, we can't grow trees on top of our homes to offset this loss, but a green roof may not be out of the question.

If you live in a city, you may be familiar with the urban heat island effect. Cities are full of large buildings, metal, concrete and asphalt. All of these things absorb large amounts of heat. As a result, the temperature in

a city can be much higher than that of the surrounding countryside. Green roofs can actually lower the temperature and create a more comfortable environment within a city's limits [source: Green Grid Roofs].

Another serendipitous byproduct of green roofs is noise reduction [source: Hydrotech USA]. That's right. Green roofs can actually help dampen sound from outside your house and keep sound that's inside from getting out. You'll be able to play your music louder without bothering your neighbors. This might seem unnecessary in a more rural setting, but in a city, it can be incredibly advantageous, blocking out the sound of traffic and sirens.

Green roofs can also help to improve air quality. Plants literally purify the surrounding air through their natural processes. Think of it like a water filtration system. In fact, speaking of water, green roofs filter that, too. The vegetation on a green roof helps absorb pollutants from rainwater before it evaporates back into the atmosphere.

The main drawback of all the approaches is cost. Some roofs—typically

older ones—may not be strong enough to handle the weight. Standard

insurance policies may construe a green roof as a structure that can

create “standing water” damage, which a policy probably will not cover unless it is amended. Extensive roofs

typically require minimal maintenance and an occasional dose of slow-release fertilizer; intensive roofs

require more ongoing attention. Both styles, however, can turn a hot, bald roof into a pleasant space for

coffee breaks, lunch, sunbathing or a simple breath of fresh air.

Source: http://tlc.howstuffworks.com/home/green-roof-save-money1.htm and Scientific American Magazine, April 30, 2008

Conditions for this Green Design Feature to be Practical: Could work anywhere plants will grow!

Green Design Feature: Collecting Rain and Snow

Description:

The simplest way to collect rainwater is to just put large containers outside on the roof or in the

yard. However, you would need a large surface area to collect enough usable water. Another simple method

to collect rainwater is to use some rain barrels. These large barrels with a spigot are commercially

available. They collect the rain water that come from a roof's rain gutter or downspout and multiple barrels

can be linked for more water storage. If you are the do-it-yourself type, here is a great video from HGTV

on how to make your own rain barrel.

In areas with snow, it is possible to harvest quite a bit of water every winter by simply saving snow in large

tanks or barrels. Once the snow melts you will have a good amount of water stored up. This is fairly simple

to do as long as you have space for the containers. If you have to shovel snow out of your driveway anyway

then it does not hurt to save some of it for later use.

Generally, you should not drink the water you collect because there are

various forms of pollution and dirt as rain falls onto various surfaces. It is

possible to set up a treatment system that cleanses the water to make it

drinkable, but the systems could be costly. The most economic use of col

lected water is probably gardening since plants thrive on rain anyway. The

collected water can also used for the following purposes:

Washing vehicles or buildings

Flushing or washing toilets

Mopping the floor

Laundry

Recharge the aquifer by redirecting water from storm drains

Drinkable water is actually a very precious resource and Americans often waste it because it just does not

seem very expensive. Having your own rainwater supply will probably not cut your water bills significantly

unless you invest in a full treatment system and stop using municipal water all together. Even if you do not

go to that extreme, using stored rainwater is great for the environment and would definitely help in times of

drought when water usage restrictions are in place.

Author: Xin Lu, http://www.wisebread.com/how-to-conserve-water-by-harvesting-rain-or-snow

Image: http://green.blogs.nytimes.com/2009/06/29/the-legalities-of-rainwater-harvesting/

Conditions for this Green Design Feature to be Practical: Would work anywhere, especially if there

enough rain to collect, but it doesn’t rain every day, or even every few days, and you need to be able to water your plants.

Green Design Feature: Insulation

Description:

Most places people live aren't a comfortable 67°F to 78°F (19°C to 26°C). To stay comfortable, we heat and cool our houses. Insulation slows the flow of heat into or out of a house. While heat can move three ways (conduction, convection, and radiation) it rarely moves in only one of them. Except in outer space, all three mechanisms are working together in varying degrees. Different insulation materials have different success at slowing these heat-flow mechanisms. Heat flows from hot to cold; it can’t be stopped, but it can be slowed

If we measure the rate at which heat flows through a building material or building assembly—for example, a

wall or a roof—we can calculate a number (the R-value) to indicate its insulating ability. The higher a

material’s R-value, the better the material is at resisting heat flow through conduction, convection, and

radiation (outlined above).

Thicker is better In cold weather, a puffy parka holds in your body heat. Insulation does the same thing for a house. The thicker the insulation, the better it works to reduce heat flow from the inside of a home to the outside during winter, and from outside to inside during summer. The thermal barrier of a home should consist of a continuous layer of insulation on all sides—including the lowest floor, the exterior walls, and the ceiling or roof. Doubling the thickness of insulation will double the insulation's R-value, cutting heat loss in half. Each time the insulation layer is doubled in thickness, this rule applies. The energy saved per year by doubling insulation from R-10 to R-20, however, will be considerably more than the energy saved by doubling insulation from R-20 to R-40, because of the law of diminishing returns. In some cases, like an attic, it’s worth piling on more insulation because there is plenty of room. It’s much more expensive to add that much insulation to exterior walls.

Source: http://www.greenbuildingadvisor.com/green-basics/insulation-overview

Conditions for this Green Design Feature to be Practical: Insulation works anywhere -in cold

environments it keeps the heat in, in warm environments it keep the heat out. You might not need as much insulation if you r location has comfortable temperatures all year round.

Green Design Feature: Building with Recycled Materials

Description:

Flooring: Flooring is good place to start when trying to make greener building choices. Some woods are

less renewable than others, and carpet often contains VOCs (volatile organic compounds) that have a

negative effect on indoor air quality. Bamboo has become a popular choice for flooring, since it

replenishes very quickly. Cork, which is removed from the outside of a living tree at intervals, is attractive,

natural, very renewable and gentle on the human body. Other green flooring options include sisal,

eucalyptus, recycled carpet tiles, recycled rubber, wool carpeting, linoleum and reclaimed wood.

Cement: On driveways and walkways, specially engineered cement that is porous and allows water to sink

in rather than run off and pollute waterways is environmentally friendly. Also, using light-colored

concrete, especially in urban areas, helps reduce temperature. For buildings, a relatively new technology

called TX Active has emerged, which actually "eats” pollution.

Insulation: Insulation is very important in green construction because it helps conserve energy. In the

past, asbestos was used for insulation, but it has since been banned or restricted in many countries

because of health hazards. Good sustainable choices for insulation are those made from recycled

newspaper and wood pulp, soy, cotton, recycled plastic or cork.

Roofing: An important feature of green roofing is its durability; sustainability can often be as simple as

avoiding or limiting waste. Composite cedar shingles resist moisture, mildew and insects, which extends

their life. Metal roofing materials that have solar reflective qualities also have advantages, especially in

hot climates. Living roofs, which are covered in hearty plant life, reduce the "heat island effect" that is

caused by a lack of evapotranspiration in areas that have a lot of concrete and asphalt surfaces.

Glass: Breakthroughs in technology have made glass a popular green building material. Windows

constructed of layered panes separated by sealed, gas-filled compartments provide insulation that

conserves energy. Additionally, windows and doors can also be covered in special low-emissivity coatings

that use or block natural solar rays to help regulate indoor temperatures. Source: http://www.ehow.com/facts_4899980_list-green-building-materials.html

And don’t forget about Earthships! The major structural building component of the Earthship is recycled automobile tires filled with compacted earth to form a rammed earth brick encased in steel belted rubber. This brick and the resulting bearing walls it forms is virtually indestructible. Earthships also use aluminum cans and glass/plastic bottles - these 'little bricks' are a great, simple way to build interior, non-structural walls. Aluminum can walls actually make very strong walls. The 'little bricks' create a cement-matrix that is very strong and very easy to build. Bottle can create beautiful colored walls that light shines through.

Source: http://earthship.com/construction-materials

Conditions for this Green Design Feature to be Practical: Anywhere will have recycled materials

available, although which ones may vary a bit by location.